ABB Motors and Drives FAQ: Answers from an Industrial Quality Inspector

I review motor and drive systems before they ship to customers—roughly 200 items a year. Four years in that seat, and I've rejected about 12% of first deliveries for spec drift. I've also heard the same questions over and over from maintenance engineers and integrators.

Here's what this guide covers:

• ABB motors vs. ABB drives—where's the line?
• What to actually check on a GE/ABB motor control center
• Stepper motor speed limits (the honest version)
• Why your brushless DC motor keeps "failing"
• Universal joint failures and real-world fixes
• An ABB motor question you probably haven't asked yet

1. What's the difference between an ABB motor and an ABB drive?

The motor converts electrical energy into mechanical rotation. The drive controls how that rotation happens—speed, torque, direction, acceleration. That's the whole thing.

ABB's motor lineup includes the workhorses: induction motors, servo motors for precision position control, and synchronous reluctance motors for high-efficiency applications. Their drive line, like the ACS880 and ACS380, adjusts frequency and voltage to match what the application needs.

What catches people off guard is how often the two get mismatched. In our Q1 2024 audit, we sampled 60 motor-drive pairs during commissioning. Eleven had parameters that didn't match the motor nameplate data. Nothing failed outright, but those motors ran below rated efficiency. On a 30 kW motor running 6,000 hours a year, a few percent efficiency loss is real money—hundreds of dollars annually, per motor.

Comparing motor catalogs side by side is easy. Making sure the motor and drive actually work as a matched pair is the part that separates a good system from a mediocre one.

2. What should I inspect on a GE/ABB motor control center before accepting it?

Motor control centers (MCCs) distribute power from a single feed to multiple motor starters and drives. GE and ABB both make solid MCCs, but the brand name is the least important part of the inspection.

Three things get my attention:

• Bus bar condition. Heat-stained copper tells you something got overloaded. In 2023, we rejected an entire MCC batch over discolored bus bars. The manufacturer insisted it was "within industry standard." Per IEC 61439, heat damage on a conductor surface is not a cosmetic issue—it's evidence of thermal stress beyond design limits. They rebuilt the batch at their cost.
• Breaker ratings vs. drawings. We found a 100 A feeder breaker where the design called for 160 A. On paper, everything matched. In reality, the circuit would have tripped whenever it approached normal load. Nameplates get misapplied. Verify each one.
• Accessibility. If a technician can't physically reach a component, it won't be maintained. That's not neglect on their part; it's a design flaw.

Also ask what's NOT included in the quote before comparing options. Terminals, cable entries, thermal testing, and commissioning support add up quickly. A quote that lists all fees upfront will look higher but usually costs less by the time the panel is live.

3. How fast can a stepper motor turn?

Realistically, a stepper motor delivers usable torque up to around 3,000 RPM. Past that, the torque curve falls off fast. The rotor can spin faster, but it won't carry a load.

When I first started specifying motors, I assumed a stepper would go as fast as I wanted if I supplied enough voltage and a good driver. Three failed prototypes later, I learned to read torque-speed curves before writing the PO. (That lesson cost me two weeks of schedule and some bruised pride.)

Steppers are for positioning. If you need continuous high-speed rotation, a brushless DC motor or a servo motor fits better. Need precise angular positioning with repeatability? The stepper is still a sensible call.

There's no secret trick to making a stepper outrun its curve. Pick the motor that matches your load profile, or let the drive supplier size it for you.

4. Why does my brushless DC motor keep failing?

Your motor might be perfectly fine. I know how that sounds, but hear me out.

I started logging BLDC failure modes in 2022. After reviewing lots of returned units, here's the pattern:

• Bearing wear. Noise, vibration, rough idle. Replace the bearing, not the motor.
• Connector failure. Vibration works connector pins loose. The motor runs intermittently. That looks like an electrical fault, but tightening the connector takes minutes. Swapping the motor takes hours and costs hundreds of dollars.
• Driver electronics overheating. Poor cabinet ventilation kills the driver, not the motor.

Of every ten "failed" BLDC motors we analyzed, only three actually needed replacing. The other seven needed bearings, connectors, or airflow. So glad we started tracking this—we've saved clients a lot of unnecessary motor purchases.

5. Why did my universal joint fail after only eight months?

Universal joints transmit power between shafts at angles. They handle the job well as long as the operating angle stays modest and the joint gets lubricated. Skew either of those and you'll be shopping for replacement joints.

Three common killers:

• Operating angle too steep. A U-joint at 15 degrees wears out fast. Cut the angle to about 5 degrees and it can run for years.
• No grease. If the zerk fitting is buried and unreachable, the maintenance crew won't lube it. (Not that anyone thinks about that at install time.)
• Misalignment. Parallel misalignment sets up constant vibration and hammering.

Real case: a client near Asheville had a motor driving a conveyor through a U-joint angled at about 15 degrees. Joints were failing every 8–10 months, every time. The fix wasn't a premium joint—it was a new mounting bracket that reduced the angle to about 5 degrees. That was three years ago. Still running.

6. Should you pick an ABB synchronous reluctance motor for your next project?

This is the question people don't ask, but they should. For fans, pumps, and compressors driven at constant speed through a VFD, synchronous reluctance motors are worth serious consideration.

ABB's synchronous reluctance motors (IE4 and IE5 efficiency classes) use a magnet-free rotor. No rare-earth magnets, no magnet supply chain concerns, no demagnetization risk. The rotor is simpler and generates less internal heat than a comparable induction rotor.

There's a catch: these motors only run from a matched drive. No drive, no sync-reluctance. And if your facility already runs a standardized induction motor fleet, new technology means new spare parts and new training for the crew. Those costs matter.

It took me years to understand that motor selection is a system decision, not a component decision. Efficiency class, drive compatibility, spare parts, maintenance skills—all of it feeds the total cost of ownership. The motor's purchase price is usually the smallest line item in that picture.